Amino AcidsL-Theanine

L-Theanine inhibits neuroblastoma cell proliferation via Slc38a1 uptake

L-Theanine inhibited proliferation of NSC-34 mouse motor neuron-like hybrid cells, with complete alleviation by co-administration of α-(methylamino) isobutyric acid or leucine, suggesting uptake via Slc38a1 and excretion via Slc7a5. Inhibition occurred even without glutamine and did not correlate with mTOR phosphorylation changes.

Last updated: Jul 7, 2026•0 RCTs•📖 Read as article →

Evidence Score

Evidence Score24/100
Human RCT☆☆☆☆☆
Meta-analysis☆☆☆☆☆
Mechanism★★★★★
Safety★★★★☆
Confidencelow

Study Evidence

Study 1. L-Theanine Uptake via Solute Carrier Family 38 Member 1 Inhibits Neuroblastoma Cell Growth.

observational

Kawada K, Matsushima Y, Nakamura R, Nishio M, Watanabe Y, Araki S, Sudo T, Yoshikawa S, Shibata M, Kinjo T, Uno K, Higashiura Y, Yamamuro A, Ishimaru Y, Yoshioka Y, Maeda S, Kuramoto N · Neurochemical research (2025)

Participants: N/A
Duration: N/A
Intervention: L-Theanine (L-gamma-glutamylethylamide) treatment on neural cell lines
Outcome: Proliferation inhibition of NSC-34 cells
Effect Size: N/A
Population: NSC-34 mouse motor neuron-like hybrid cells and other neural cell lines (in vitro)

Result:

PubMed: 41410739DOI: 10.1007/s11064-025-04635-0

Mechanism Graph

L-Theanine is taken up into cells via solute carrier family 38 member 1 (Slc38a1)
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L-Theanine is excreted from cells via solute carrier family 7 member 5 (Slc7a5)
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Intracellular theanine inhibits cell proliferation through an unclear mechanism independent of glutamine and mTOR phosphorylation
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Result: Inhibition of neuroblastoma cell growth

Limitations

  • ⚠Molecular mechanism of theanine's anti-proliferative effect after cellular uptake remains unclear
  • ⚠Study conducted only in animal cell lines (in vitro), not in human subjects or in vivo models

Frequently Asked Questions

What is L-Theanine?▼

L-Theanine is an amino acid and umami component found in green tea, known for its effects on the central nervous system such as stress alleviation and sleep maintenance.

How does L-Theanine inhibit neuroblastoma cell growth?▼

L-Theanine enters cells via the glutamine transporter Slc38a1 and is excreted via Slc7a5. Once inside, it inhibits cell proliferation through an unknown mechanism that does not depend on glutamine or mTOR signaling.

What cell types were tested in this study?▼

The study tested several neural cell lines, with the strongest inhibition observed in NSC-34 mouse motor neuron-like hybrid cells.

Is this study relevant to human sleep?▼

The paper mentions theanine's known effects on sleep and stress, but this specific study focuses on its anti-proliferative effects on neural cells, not sleep outcomes.

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References

  1. 1.Kawada K, Matsushima Y, Nakamura R, Nishio M, Watanabe Y, Araki S, Sudo T, Yoshikawa S, Shibata M, Kinjo T, Uno K, Higashiura Y, Yamamuro A, Ishimaru Y, Yoshioka Y, Maeda S, Kuramoto N. "L-Theanine Uptake via Solute Carrier Family 38 Member 1 Inhibits Neuroblastoma Cell Growth.." Neurochemical research, 2025. PMID: 41410739 DOI: 10.1007/s11064-025-04635-0
Disclaimer: This content is for educational purposes only and is not medical advice. Evidence scores reflect the quality and quantity of available research, not clinical recommendations. Always consult a healthcare professional before starting any supplement or intervention.